Hydrocarbon inhibitors for use in oil refinery heat exchanger



United States Patent 3,32%,283 HYDROCARBON INHIBITORS FOR USE ]N OIL REFINERY HEAT EXCHANGER Richard L. Godar, St. Louis, Mo assignor to Petrolite Corporation, Wilmington, Del., a corporation of Delaware No Drawing. Continuation of application Ser. No. 138,276, Sept. 15, 1961. This application Jan. 6, 1965, Ser. No. 423,847

8 Claims. (Cl. 20848) This application is a continuation of application Ser. No. 138,176, filed on Sept. 15, 1961, and is a continuation-in-part of application Ser. No. 50,558, filed on Aug. 19, 1960 and is a continuation-in-part of application Ser. No. 138,275, filed on Sept. 15, 1961, all abandoned.

This invention relates to a method of chemically treating hydrocarbon liquids which contact surfaces under high temperature conditions in order to inhibit, prevent and/ or reduce the deposition of substances thereon. More specifically, this invention relates to the chemical treatment of the metal surfaces in contact with petroleum hydrocarbon liquids under conditions of high temperatures whereby said liquids tend to form deposits on such metal surfaces. This invention also relates to compositions employed in these processes.

In the processing of hydrocarbon liquids, particularly petroleum hydrocarbon liquids, elevated temperatures are often used in many necessary and important operations. To handle liquids at elevated temperatures, heat exchangers and the like devices are often employed to control the heat transfer rate from one operational step to an other. When hydrocarbon liquids contact hot metal surfaces, there is sometimes a tendency for the liquid to decompose or undergo a chemical reaction that manifests itself in the form of deposits. These deposits may be either coke-like or they may be in the form of tenacious, soft, sticky sludges which adhere to hot surfaces. Adherence of deposits, rather than deposit-formation itself is the essence of the problem, in contrast to fuel storage where residue in the oil itself creates the problem.

The problem is well recognized in the art--Note Petroleum Products Handbook, Guthrie (McGraw-Hill, 1960) pages 1-13, US. Patent 2,908,824 and elsewhere.

These deposits tend to materially decrease the heat transfer capacities of the metal surfaces and hence increase operating expenses. These deposits also require additional effort and time to remove and to restore the equipment to its original operating efficiency.

Petroleum refinery operations often encounter the above described conditions in many stages in the refining process. These deposits form on heat transfer surfaces at temperatures as low as about 200-225 F. and may be evidenced at temperatures as extreme as 800 F.

It is practically impossible to prevent these deposits by coating the metal surfaces with a protective permanent coating due to the possible loss of heat transfer. In addition, the large volume of liquid that contacts such equipment increases the problem of treating metal surfaces in petroleum processing to prevent high temperature deposits.

It would be advantageous if a chemical agent could be added in an extremely small amount to a hydrocarbon liquid which tends to form high temperature deposits whereby such deposits would be prevented. It would also be desirable if such a chemical would not only prevent such deposits but would also remove them without necessitating the stoppage of a given operation. It therefore becomes an object of the present invention to prevent the formation of high temperature deposits on metal surfaces by chemical means.

Another object is to furnish a chemical which when added to a hydrocarbon liquid will prevent the depositforming tendencies of said liquid when it contacts metal surfaces at elevated temperatures.

A further object is to provide a chemical treatment which will prevent the formation of high temperature deposits by petroleum hydrocarbon liquids in contact with heat transfer equipment.

Yet another object is to furnish a chemical treatment capable of being combined with a thermally unstable, deposit-forming liquid whereby said liquid will not form deposits upon metal surfaces at elevated temperatures.

Still another object is to provide a chemical treatment which will remove high temperature deposits from metal surfaces of petroleum refining equipment without the necessity of stopping the operations of such equipment. Other objects will appear hereinafter.

In accomplishing these objects in accordance with the invention it has been found that new and improved results in preventing, inhibiting and/or reducing the formation of deposits from petroleum hydrocarbon liquids during the processing thereof at elevated temperatures, particularly at temperatures within the range of about 200-225 F. to 800 F., are obtained by adding to, preferably by dissolving or dispersing in the hydrocarbon liquid the anti-fouling agent of this invention.

In application Ser. No. 50,558, filed Aug. 19, 1960, I have described and claimed various compositions useful as anti-fouling agents.

These anti-fouling agents include a partial ester of a polyol and a carboxylic acid, said partial ester being soluble and/or dispersible in the hydrocarbon liquid, wherein at least one but not all of the hydroxy groups of the polyol are esterified with a carboxylic acid. Although the partial ester can be employed alone, its activity is enhanced by one or more of the following oil soluble or dispersible auxiliary agents:

(1) An oxylated phenol.

(2) A copolymer of (a) an acrylic type ester and (b) vinyl pyrrolidone (sometimes referred to herein as oopolymer).

(3) A metal deactivator.

I have now discovered that the compositions described therein can be rendered more effective as anti-fouling agents, particularly at temperatures above 500 F. by incorporating therein salts of an organic sulfonic acid which are at least oil dispersible or oil soluble.

The anti-fouling agents employed in S.N. 50,558 are described therein as follows:

The anti-fouling agent employed in this invention is a partial ester of a polyol and a carboxylic acid. Althoughpartial esters formed from monocarboxylic acids are preferred, partial esters of polyols and polycarboxylic acids, particularly dicarboxylic acids, can be employed provided they are soluble or dispersible in hydrocarbon, for example a partial ester polymer of a diol and a dicarboxylic acid Examples of polycarboxylic acids include the alkylene polycarboxylic acids, the arylene polycarboxylic acids,

the aralkylene polycarboxylic acids, etc. Specific examples of dicarboxylic acids include where B is alkylene, arylene, etc., for example, succinic, alkenyl succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, dimeric etc. acids. Examples of aromatic dicarboxylc acids include phthalic, isophthalic, terephthalic acid, biphenyl dicarboxylic acid, etc.

Examples of polyols include diols, triols, tetrols, pentols, hexols, etc. for example glycols, glycerol, polymerized glycerols, trimethylol ethane, sorbitol, mannitol, mannide, mannitan, sorbide, sorbitan, pentaerythritol, etc.

Examples of glycols include the alkylene glycols, HO- alkylene-OH, for example where the alkylene group has 2-20 or more carbons but preferably 28 carbons, with an optimum of 2-4 carbons and polyoxyalkylene glycols, for example of the formula, HO(all:ylene 0),,H where the alkylene group is, for example, ethylene, propylene, butylene, mixtures of blocks thereof, etc. and n is 1-100, for example 1-20, but preferably 1-10. Non-limiting examples include ethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, tripropylene glycol, pentaethylene glycol, pentamethylene glycol, decamethylene glycol, hexadecamethylene glycol, heptadecaethylene glycol, the Pluronics of Wyandotte Chemical Company, etc.

A class of partial esters utilizable in this invention include esters of hexitans and hexides obtained by dehydraing sorbitol, and certain polyoxyalkylenes, such as the polyoxyethylene and derivatives thereof. These compounds are known as Spans and Tweens, which are manufactured by the Atlas Powder Company, According to the manufacturers literature, these esters are prepared by first dehydrating sorbitol to produce a mixture of hexitans and hexides having the following formula:

and condensed turan ring HO-CH l CH: CH-CH-OH This mixture of hexitans and hexides is then esterified by reacting it with one or more moles of a fatty acid to form the Spans. The Tweens are similar thereto except that the unesterified hydroxy groups in the hexitans and hexides have polyoxyethylene chains added thereto. Nonlimiting examples of the esters contemplated herein are sorbitol anhydride monolaurate, sorbitol anhydride monomyristate, sorbitol anhydride monopalmitate, sorbitol anhydride monostearate, sorbitol anhydride monooleate, sorbitol anhydride monolinoleate, and polyoxyethylene derivatives of the foregoing monoesters. Further data on the monoesters utilizable herein are attainable in a brochure entitled Atlas Surface Active Agents published in 1948 by the Atlas Powder Company. Reference should be made thereto, and it is considered to be a part of this specification.

I advantageously employ a compound of the formula where R is an alkylene radical derived from an alkylene oxide, for example ethylene oxide, propylene oxide, butyl optimum of 10-20 carbons. In the preferred embodiment the polyol should have at least one unesterified hydroxyl group, for example in the case of glycerol, one or two of the hydroxyl groups thereon are esterified by the carboxylic acid. These compounds, having at least one unesterified hydroxyl group, will be referred to herein as partial esters and can be expressed generally as where R is the radical derived from the carboxylic acid and G is the radical derived from the poly and x and y are each at least 1 and the sum of x+y equals the number of hydroxyl groups originally present in the polyol.

Although the partial esters alone prevent fouling, their 1 efficiency is often enhanced by the presence of other auxiliary chemical components.

One of these auxiliary chemical components is an oxyalkylated phenol, preferably an oxyallcylated substituted phenol, such as an alkyl phenol, for example those of the formula where R" is a substituted group, for example, a hydrocarbon group, such as an aryl radical, an aliphatic radical, preferably alkyl, for example containing 1-3() or more carbon atoms, such as 4-20 carbons, but preferably 8-18 carbons (including substituted groups containing other elements besides carbon and hydrogen, such as alkoxy, etc.), A is an alkylene radical derived from an alkylene oxide such as ethylene, propylene, butylene, etc. oxides added singly, mixed, blocked, etc., x represents the number of moles of alkylene oxide for example 1 to or more, such as 1-20, preferably l-10 and m represents the number of substituted groups, for example l-2.

An example of an oil-soluble or dispersible polyoxyalkylene ether of an alkyl phenol is prepared by alkylating phenol with an olefin containing at least 6, and preferably 9 to 18, carbon atoms under condtions adapted to furnish an alkyl phenol reaction product having an average of l to 2 alkyl groups per phenol molecule. The olefins employed for the alkylation of phenol may be straight-chain olefins, such as those produced in the Fischer-Tropsch synthesis; branched-chain olefins, such as those formed in the polymerization of propylene and butylene; or mixtures of branchedand straight-chain olefins which are recovered from a heavy cracked naphtha by selective adsorption with silica gel. Alcohols or alkyl chlorides with car-hon chains of suitable length may also be employed as the alkylating agents. Preferably, mixtures of C to C branched-chain olefins produced by polymerizing propylene are thus employed. The resulting alkyl phenol product which may contain from 15 to 20% by weight of dialkyl phenols, is condensed with ethylene oxide, propylene oxide, butylene oxide, individually or in combination, or a corresponding glycol. Ethylene oxide is usually preferred. Particularly suitable alkyl phenyl polyoxyalkylene others are alkyl phenyl polyoxyethylene ethers containing an average of 10-20 alkyl carbon atoms and l to 10 oxyethylene groups.

Another auxiliary chemical component is the copolymer derived from an acrylic ester of the formula:

and N-vinyl-Z-pyrrolidone, for example a copolymer containing the following units:

having a molecular weight for example of at least 50,000, for example 50,000-500,000, or higher, but preferably 100,000-400,000 with an optimum of 300,000-400,000 of which vinyl pyrrolidone comprises at least 1% by weight of the copolymer, for example 130%, but preferably 315% with an optimum of 5-10%; where Y is hydrogen, a lower alkyl group such as methyl, ethyl, etc., Z is an hydrocarbon group having, for example, 1-30 carbon atoms, but preferably 8 to 18 carbon atoms. These polymers are preferably acrylic or methacrylic polymers, or polymers derived from both in conjunction with vinyl pyrrolidone. The Z group on the polymer, which can be the same throughout or mixed, can be octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, octadecyl, etc. Lower alkyl groups can also be employed such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, etc., but they preferably are employed as copolymers of the higher Z groups, for example a copolymer of dodecyl methacrylate and methyl acrylate, etc. The acrylic ester units may be derived from one or more acrylic type monomers and may be fully acrylic or fully methacrylic or both acrylic and methacrylic. The polymer may be random, block, graft, etc.

Also, Z may also be an alkylated aromatic group such as butyl phenyl, amyl pheuyl, etc., or a cycloaliphatic group such as cyclohexyl. Thus, non-limiting specific examples of suitable monomeric esters are: methyl acrylate, ethyl .acrylate, propyl methacrylate, amyl acrylate, lauryl acrylate, cetyl acrylate, octadecyl acrylate, amyl methacrylate, lauryl methacrylate, cetyl methacrylate, octadecyl methacrylate, amylphenyl methacrylate, cyclohexyl methacrylate, etc., including the analogous acrylate or methacrylate esters. Copolymers of the above and other acrylic esters may be used, for example, a copolymer of methyl or ethyl acnylate .and dodecyl methacrylate in conjunction with vinyl pyrrolidone. However, it should be understood that this description' does not preclude the presence of small amounts of unesterified groups being present in the polymer, i.e. approximately 5% or less of where Z-=H.

It should be understood, of course, that when the above compounds are polymerized, the polymerization should not be carried to such an extent as to form polymers which are insoluble or non-dispersible in the petroleum hydrocarbon used. The polymerization may be carried out by methods known to the art, such as by heating mildly in the presence of a small amount of benzoyl peroxide, but the method of polymerization is not part of this invention. For examples of acrylic-vinyl pyrrolidone copolymers see French Patent 1,163,033.

Another auxiliary chemical component is a metal deactivator for example those conveniently employed in deactivating copper, iron and other metals from hydrocarbon systems. Typical examples are those described in US.

6 Patent 2,282,513. Of course, one skilled in the art is aware that many other metal deactivators are known and can be employed herein.

The compounds employed as metal deactivators are preferably of the type of Schilfs bases and may be represented by the formulae:

wherein A and B each represents an organic radical and preferably a hydrocarbon radical. In Formula 2 A and B each preferably represents an aromatic ring or an unsaturated heterocyclic ring in which the hydroxyl radical is attached directly to a ring carbon atom ortho to the CH=N group. R represents an aliphatic radical having the two N atoms attached directly to different carbon atoms of the same open chain.

Typical examples of aldehyde and polyamines employed in preparing these Schiff bases includes the following:

Aldehydes Benzaldehyde Z-methylbenzaldehyde 3-methylbenzaldehyde 4-methylbenzaldehyde Z-methoxybenzaldehyde 4-rnethoxybenzaldehyde a-Naphthaldehyde b-Naphthaldehyde 4-phenylbenzaldehyde Propionaldehyde n-Butyraldehyde Heptaldehyde Aldol 2-hydroxybenzaldehyde Z-hydroxy-6-methylbenzaldehyde 2-hydroxy-3-methoxybenzaldehyde 2-4-dihydroxybenzaldehyde 2-6-dihydroxybenzaldehyde Z-hydroxynaphthaldehyde-l 1-hydroxynaphthaldehyde-2 Anthrol-Z-aldehyde-l 2-hydroxyfiuorene-aldehyde-1 4-hydroxydiphenyl-aldehyde-3 B-hydroxyphenanthrene-aldehyde-4 1-3-dihydroxy-Z-4-dialdehydebenzene Z-hydroxy-S-chlorobenzaldehyde 2-hydroxy-3 -5-dibromobenzaldehyde 2-hydroxy-3 -nitrobenzaldehyde 2-hydroxy-3-cyanobenzaldehyde 2-hydroxy-3-carboxybenzaldehyde 4-hydroxypyridine-aldehyde-3 4-hydroxyquinoline-aldehyde-3 7 -hydroxyquinoline-aldehyde-8 Polyamines:

Ethylenediamine 1-2-propylenediamine 1-3-propylenediamine 1-6-hexamethylenediamine 1- 1 O-decamethylenediamine Diethylenetriamine Triethylenetetramine Pentaerythrityltetramine I-Z-diaminocyclehexane Di-(b-aminoethyl) ether Di-(b-aminoethyl) sulfide The partial ester comprises of at least 5% of the antifouling composition such as 5 to for example,

7 10 to 80%, preferably 15 to 60% with an optimum of 30 to 40%.

Where other auxiliary chemical components are employed. in conjunction with the partial ester, they are em- [B. Cyclic type] [1200121 HZ HZ A IZ g furan, pyran or condensed furan ring.

ployed in the following percentages of the total com- 5 posltion. n z x gg gg Oxyalkylated phenl095%, for example, 10 to 80%, RC- preferably 30 to 70%, With an optimum of 40 to 60%.

The copolymer-O to 35%, for example, 1 to 25%, 16..." 1 3 Lauryl Tween 21 preferably 5 to 15% With an optimum of 8 to 12%. :1 g 2;-

Metal deactivators-0 to 10%, for example, .0001 to 19-.-" 3 3 Tween s5 8%, preferably 0.1 to 5% with an optimum of 0.5 to 2%. 39:: 3 23- Thus, the partial ester may be eifectively employed 1 3 Tween so. alone or in conjunction with the oxyalkylated phenol, 2:: i 2 $323 and/ or the copolymer and/ or the metal deactivator. How- 1 3 p ever, it should be noted that the optimum amounts of each Will vary with the fuel, the COl'lditiOnS employed, the TABLE IL-OXYALKYLATED PHENOLS temperatures, etc. (0 MHOH Where the additive includes (1) the partial ester, (2) the oxyalkylated phenol and (3) the copolymer, typical Weight percentage compositions are as follows:

R A. Broad range: m

(1) 5 to 95 Ex. R 111 A0 11 (2) 75 to 4 (3) 20 to 1 1 EtO 1o 2 EtO 20 B. Preferred range: 2 gtg 1o 1 t (1) 15 to 8;) 1 m 2 70t 2 E1: 3 o 1 2 EtO 15 (3) 15 to2 1 mo 25 2 PrO 10 C. Optlmum range: 2 13110 5 1 25 to 45 12 D d I f i 18 (2) 61 to 47 3 1 g 13 to 8 oxy P50 3 14. Octadecyl 1 7 n d c d a" 1 EtO 15 y rogena 0 car mo 20 Where the metal deactivator is employed, 1t 1s .0001

TABLE IIL-VINYL PYRROLIDONE-ACRYLIC ESTER-TYPE RESINS Vinyl Pyr- Ex. Monomer 1 Monomer 2 Monomer 3 rolidone, M01 Ratio Av. Mol

percent 122:3 Weight by wt.

1 Tridecylmethacrylate Octadecyl methacrylate 7.5 1 1 300,000 2 Dodecylrnethacrylate 1 n. 10 2 rlo Butyl acrylate 15 2:1 400, 000 4. Octadecyl methaerylate 5 450, 000 5 Tridecyl methacrylatm. l 20 350,000 6. Octadecylmethacrylate- Methyl methacrylate 10 3:1 500,000 7. Dodecyl methacrylate Ethyl acrylnte 5 4:1 400,000 8 Cetylmethacrylate Octadecyl methacrylate Butylmethacrylate 7.5 2:1:0.5 350,000

to 8%, preferably 0.1 to 5%, with an optimum of 0.5 to 2%, based on the above mixture.

The following compounds are satisfactorily employed as anti-foulants.

TABLE I.PARTIAL ESTERS [A. Linear typo] Ex. Polyol Acid Mole Ratio Polyol/Acid Ethylene glycol Dodecanoic 1:1 Diethyleue glycoL Naphthenic (MW 220230) 1:1 Propylene glycol Stearic 1:1 Dipropyleue glycol Laurie 1:1 Adipic 2=1 U Laurie 1:1 Phthahc 2:1 Octanorc 1:1 01810.. 1:2 .1" Laurie 1:1 H0(EtO) H Trimethylnonauom 1:1 H0(EtO)i(PrO) (EtO) H Hoxanoic 1:1 Pentaeryritol Laurie 1:3 Sorbitnl 0leie 1:2 Maunitol Palmitic 1:3

The specification of S.N. 50,558 is hereby incorporated by reference into the present application. The compositions described in S.N. 50,558 can be rendered more effective by incorporating therein salts of organic sulfonates. This is particularly true when the temperatures employed are above 500 F., such as 550680 F. or higher.

The organic sulfonate salts may be represented by the following formula, (RSOQ Me, examples of which are petroleum sulfonate salts, alkyl aryl sulfonate salts, for example those of the formula R -ArSO Me, Where Me represents a salt forming moiety, for example the elements of Group I-A, Group II-A, etc. of the periodic table, ammonium and amine salts thereof, etc. Ar represents an aromatic group, for example, phenyl, naphthyl, higher condensed aromatic systems, and R represents a substituted group, for example, a hydrocarbon group such as alkyl, x is an integer determined by the valence of the metal, and n represents the number of positions on the aromatic nucleus which are substituted. Further examples of alkyl aryl sulfonates are presented in the following table:

TABLE IV.ALKYL AROMATIC SULFONATES [Aromatic nucleus] Benzene Toluene Xylenes, ethyl benzene, mesitylene, cymene, etc. Phenol Cresols, xylenols, and lower alkylated phenols Phenol ethers, anisole, phenetole, etc.

Diaryl ethers, diphenyl ether, etc. Naphthalene I. Naphthols J. Naphthol ethers K. Diphenyl L. Phenyl phenols M. Diand triphenyl methanes N. Benzoins and desoxybenzoins O. Rosin and modified rosins [Alkyl group] Methyl and ethyl Propyl Butyl Amyl Hexyl Heptyl (7) Straight-chain octyl (8) Octyl, Z-ethylhexyl (9) Octyl, diisobutyl (10) Nonyls (ll) Decyls (12) Keryls (l3) Straight-chain alkyl C (14) Straight-chain hydroxylated or unsaturated alkyl, oleyl, ricinoleyl. These may be attached to one or more aromatic nuclei.

(15) Mixed alkyl from cracked parafiin wax olefins (16) Mixed alkyl from polymers of C3-C7 monoolefins (17) Mixed alkyl from naphthenes (18) Terpenoid, from terpene olefins or alcohols (19) Oleic acid derivative condensates, condensed through the double bond of the oleic chain.

(20) Acyl groups, i.e., alkyl aromatic ketones usually made by a Friedel-Crafts acylation reaction.

(21) Branched alkyl group derived from a ketone or aldehyde.

(22) Olefins from miscellaneous synthetic processes.

(23) Steroid and complex alkyl-aromatic The compositions of S.N. 50,558 can be improved by adding thereto sufiicient sulfonate to improve the antifouling properties thereof, for example at least 5% by weight organic sulfonate, such as 5 to 95%, for example 20 to 80%, but preferably 30 to 70% with an optimum of 40 to 60%. Of course, the amount of effective sulfonate will depend, among other things, on the specific sulfonate employed, the hydrocarbon treated, etc.

The conditions encountered in refinery operations are simulated by exposing petroleum products taken from various refineries to high temperatures heat exchange tubes in the absence of and in the presence of the antifouling compositions of this invention.

A CFR fuel coker model 01FC is employed to simulate these conditions. It is described in CRC Manual No. 3, March 1957, published by the Coordinating Fuel and Equipment Research Committee of the Coordinating Research Council, Inc. The standard procedure is employed except that the equipment is modified so as to bypass the filter section.

The conditions of the test are as follows:

Test time min 60 Test temperature F 575 Test pressure p.s.i 250 Test rate of flow lbs./hr 3 The amount of fouling occurring is measured by observing the preheater (or heat exchanger) tube before and after the test to determine the amount of deposits formed on the preheater tube. One finds the tube appearance to correspond with the amount of fouling measured by gravimetric means, for example, a tube showing 2.0 mg. deposit will look considerably cleaner than one showing 4.0 mg. deposit. Gravimetric results generally corroborate the results obtained by inspection of the tube.

The following tests were run on a straight run naphtha charge. In the following tests, the additive is designated as follows:

F. (Composition of S.N. 50,558):

Parts by weight Dinonyl phenol-{-10 M EtO 5.2 Laurie acid ester of diethylene glycol 3.5 Terpolymer of lauryl methacrylate cetyl-stearyl methacrylate, and vinyl pyrrolidone 1 A. Blend of alkyl aryl polyether alcohol:

(0 CHzCHzhOH alkyl and organic sulfonates(SO -,Na) both oil soluble.

alkol ed in the following table.

TABLE VI The tests in the following table were run on a catalytic reformer unit charge.

Residue on Ex. Additive Ratio P p m Exchanger Tube 1 None 6. 1 2 \I 40 3. 9 3 F+M 1:1.2 37 2.9

All of the organic sulfonates employed in the above table are oil soluble and can be described by the formula where Me is a metal of valence x, and n is greater than 20.

The above test are typical of the screening tests employed in evaluating anti-fouling additives. After being screened in this manner, the anti-fouling additives are employed in petroleum refinery operations. By means of the above tests, the most effective additive is selected for the particular hydrocarbon under consideration and the additive is then employed in the specific operation.

The anti-fouling additive can be employed in refining crude petroleum as well as in the treatment of any component thereof which are exposed to high temperatures including the light distillates, for example light naphthas, intermediate naphthas, heavy naphthas, etc.; middle distillates, for example kerosene, gas oil, etc; distillate lube oil stocks, for example, white oil, saturating oil, light lube oil, medium lube oil, heavy lube oil, and the like.

In addition, the additive can be employed with other hydrocarbons such as xylene, benzene, purified hydrocarbon compounds, etc. In addition, they can be employed under certain conditions with non-hydrocarbons, such as alcohols, phenols, etc. For example, they can be employed in a toluene extraction tower and stripper which process comprises mixing phenol and toluene in an extraction whereby phenol extracts impurities from toluene and the raflinate is subsequently removed. Thereafter the mixture is sent to a stripper where the toluene is removed from the phenol by distillation. The remaining phenol is recycled to the extractor for further use. The system is operated over a wide temperature range for example 230-425 F. Deposits in the phenol circuit cause the loss of excessive amounts of phenol. It can be used in heat transfer units used in a furfurol extraction process processing for example, intermediate distillates, parafi'in distillates, decanted oil, vacuum cylinder stock, deasphalted cylinder stock, etc.

The amount of anti-fouling agent required in this invention is subject to wide variation but in general very eifeective results have been obtained by adding relatively minute amounts of the anti-fouling agent to the hydrocarbon liquid being processed, for example, amounts may be as low as 0.5 p.p.m. in hydrocarbon liquid, for example 1 to 500 p.p.m. or higher, for example 1000 or more p.p.m., preferably 25 to 100 p.p.m., with an optimum of 35-55 p.p.m. Higher temperature requires greater concentrations. In general, the upper limit is determined by the economics of the process but other factors should be taken into consideration such as whether large amounts will have any adverse effects on present or subsequent operations. Because of the many different types of operations where bydrocarbons are heated to elevated temperatures under small amounts and it is preferable to feed them con.

tinuously or semi-continuously by means of a proportioning pump or other suitable device to the particular hydrocarbon liquid being processed or to add them in a similar manner to the apparatus in which the hydrocarbon liquid is being processed, it is desirable to incorporate the agent or a mixture of agents into a suitable solvent which will be compatible with the liquid which is to be processed. The solvent which is used to dissolve the active ingredient is also subject to some variation depending upon the solubility characteristics of the particular com:

pound employed. In some cases, even though the active mixture is insoluble in a particular solvent, it will dissolve in a combination of solvents.

In the practice of the invention it is very desirable to start the treatment with the chemicals employed for the purpose of the invention at a higher dosage and then gradually reduce the dosage to the point where fouling of the apparatus is just eliminated.

The invention is especially valuable where sour naphthas are being processed or where the oil being processed is a mixture containing some sour naphthas.

Examples of specific types of apparatus to which the chemical compositions of the invention can be added during petroleum processing are fractionating towers, stripping columns, debutanizers, depropanizers, deethanizers, heat exchangers, reboilers, hot product lines and other metal equipment (usually ferrous metal) which is brought into contact with the organic liquids being processed at relatively high temperatures. The invention makes is possible to extend the useful life of crude oil fractionating towers and other types of petroleum refinery equipment. It also makes it possible to provide cleaner inside surfaces resulting in better fractionationg, better heat exchange in coolers, far less severe plugging and less time required for cleaning and maintenance.

Having thus described my invention what I claim as new and desire to obtain by Letters Patent is:

1. A process for inhibiting in oil refining apparatus during petroleum refining operations the formation of adherent coke-like deposits and adherent tenacious soft,

sticky slugdes on, and the adhesion of said deposits and said sludges to, the hot metal heat transfer surfaces of a heat exchanger in said oil refining apparatus by a hydrocarbon liquid passing through said heat exchanger at a i temperature in excess of about 225 F. and having the tendency to undergo a chemical reaction at a temperature in the range of about 225 F. to about 800 F., said chemical reaction manifesting itself in the form of adherent coke-like deposits and adherent soft, sticky sludges, such as are usually formed during passage of said hydrocara bon liquid through said heat exchanger and in contact with the hot metal surfaces of said-heat exchanger in said oil refining apparatus at a temperature in the range of about 225 F. to about 800 F. characterized by (1) incorporating in said hydrocarbon liquid prior to a I (H0)XG-(o( J-R') where:

G is the hydrocarbon-containing moiety of a polyol, x is an integer of at least 1,

O and then esterifying said mixture by reacting it with at least one mole of a fatty acid selected from the group consisting of lauric acid, stearic acid, palmitic acid and oleic acid, and

(4) partial esters formed by first dehydrating sorbitol to produce a mixture of hem'tans and hexides having the formula HO-CH then esterifying said mixture by reacting it with at least one mole of a fatty acid selected from the group consisting of lauric acid, stearic acid, palmitic acid and oleic acid, and then adding polyoxyethylene chains to the nonesterified hydroxy groups in said hexitans and hexides, and

(B) a hydrocarbon soluble salt selected from the group consisting of (1) a petroleum sulfonate salt having the general formula wherein:

Me is a metal of valence x, x is an integer of 1-2, and n is an integer greater than 20,

(2) mixtures of petroleum sulfonate salts, each having the general formula of said salt of (1) and Me of each being different, and

(3) an alkyl aryl sulfonate salt having the formula 14 wherein:

Me is a metal of valence z, z is an integer of 1-2, Ar is an aromatic radical, R is a hydrocarbon-containing radical having 1-18 carbon atoms, and x is an integer of 13, representing the number of nuclear substituted groups on said aromatic radical, and (2) heating said hydrocarbon liquid having incorporated therein said composition in an antifouling amount to a temperature in the range of about 225 F. to about 800 F. by contact with said hot metal surfaces of said heat exchanger in said oil refining apparatus. 2. T he process of claim 1 wherein the partial ester is of the formula ll H (O alkylene) a0 GR wherein:

n is an integer of 1-10 and R is a hydrocarbon radical containing 620 carbon atoms. 3. The process of claim 1 wherein the partial ester is of the formula H(0R)2o("3R' wherein:

R is an alkylene radical having 24 carbon atoms, and R' is an alkyl group having 620 carbon atoms. 4. The process of claim 1 wherein the partial ester is 5. A process for inhibiting in oil refining apparatus during petroleum refining operations the formation of adherent coke-like deposits and adherent tenacious soft, sticky sludges on, and the adhesion of said deposits and said sludges to, the hot metal heat transfer surfaces of a heat exchanger in said oil refining apparatus by a hydrocarbon liquid passing through said heat exchanger at a temperature in excess of about 225 F. and having the tendency to undergo a chemical reaction at a temperature in the range of about 225 F. to about 800 F., said chem ical reaction manifesting itself in the form of adherent coke-like deposits and adherent soft, sticky sludges, such as are usually formed during passage of said hydrocarbon liquid through said heat exchanger and in contact with the hot metal surfaces of said heat exchanger in said oil refining apparatus at a temperature in the range of about 225 F. to about 800 F. characterized by 1) incorporating in said hydrocarbon liquid prior to contact with said hot metal surfaces of said heat exchanger in said oil refining apparatus an antifouling amount of a composition comprising (A) a partial ester selected from the group consisting of O )X II OGR Where:

1 (3) partial esters formed by first dehydrating sorbitol to produce a mixture of hexitans and hexides having the formula F O V (lla \CHGH2OH HO-CH GH-OH CHOH and then esterifying said mixture by reacting it with at least one mole of a fatty acid selected from the group consisting of lauric acid, stearic acid, palmitic acid and oleic acid, and

(4) partial esters formed by first dehydrating sorbitol to produce a mixture of hexitans and hexides having the formula wherein:

Me is a metal of valence x, x is an integer of 1-2, and n is an integer greater than 20,

(2) mixtures of petroleum sulfonate salts, each having the general formula of said salt of (l) and Me of each being different, and

(3) an alkyl aryl sulfonate salt having the formula wherein:

Me is a metal of valence z,

z is an integer of 1-2,

Ar is an aromatic radical,

R is a hydrocarbon-containing radical having 1-'18 carbon atoms, and

x is an integer of 1-3, representing the number of nuclear substituted groups on said aromatic radical, and

(C) a member selected from the group consisting (1) an oxyalkylated. hydrocarbon-substituted phenol having the formula |)A)X0H and having a molecular weight of 50,000- 500,000, unit (b) being at least 130% by weight of the copolymer, Y being selected from the group consisting of hydrogen and a lower alkyl group and Z being a hydrocarbon radical having 1-30 carbon atoms, and

(3) a Schifif base alkylene polyamine-aldehyde reaction product, and

(2) heating said hydrocarbon liquid having incorporated therein said composition in an antifouling amount to a temperature in the range of about 225 F. to about 800 F. by contact with said hot metal surfaces of said heat exchanger in said oil refining apparatus.

6. The process of claim 5 wherein the partial ester is of the formula 0 ll 11 0 alkylenehO o-a n is an integer of 1-10, and R is a hydrocarbon radical containing 6-20 carbon 7. The process of claim 5 wherein the partial ester is of the formula R is an alkylene radical having 2-4 carbon atoms and R is an alkyl group having 6-20 carbon atoms.

8. A process for inhibiting in oil refining apparatus during petroleum refining operations the formation of adherent coke-like deposits and adherent tenacious soft, sticky sludges on, :and the adhesion of said deposits and said sludges to, the hot metal heat transfer surfaces of a heat exchanger in said oil refining apparatus by a hydrocarbon liquid passing through said heat exchanger at a temperature in excess of about 225 F. and having the tendency to undergo a chemical reaction at a temperature in the range of about 225 F. to about 800 F., said chemical reaction manifesting itself in the form of adherent cokelike deposits and adherent soft, sticky sludges, such as are usually formed during passage of said hydrocarbon liquid through said heat exchanger and in contact with the hot metal surfaces of said heat exchanger in said oil refining apparatus at a temperature in the range of about 225 F.

7 to about 800 F. characterized by 1 7 (1) incorporating in said hydrocarbon liquid prior to contact with said hot metal surfaces of said heat exchanger in said oil refining apparatus an anti-fouling amount of a composition comprising (A) a partial ester having the formula and (B) a hydrocarbon soluble salt selected from the group consisting of (1) a petroleum sulfonate salt having the general formula (R Ar- S Me wherein:

Me is a metal of valence z z is an integer of 12,

Ar is an aromatic radical,

R is a hydrocarbon-containing radical having 1-18 carbon atoms, and

x is an integer of 1-3, representing the number of nuclear substituted groups on said aromatic radical, and

(C) a member selected from the group consisting of ylh (2) a copolymer of stearyl methacrylate and vinyl pyrrolidone and (3) H CH3 H (|)=NOHOH2N=C 0-011 HO@ and (2) heating said hydrocarbon liquid having incorporated therein said composition in an antifouling amount to a temperature in the range of about 225 F. to about 800 F. by contact with said hot metal surfaces of s'aid heat exchanger in said oil refining apparatus.

References Cited UNITED STATES PATENTS 2,282,513 5/1942 Downing et al. 4473 2,548,347 4/1951 Caron et al. 4463 2,786,745 3/1957 Stayner et a1 252404 3,105,810 10/1963 Miller et al. 20848 FOREIGN PATENTS 822,620 10/1959 Great Britain.

DELBERT E. GANTZ, Primary Examiner.

PAUL M. COUGHLAN, Examiner.

A. RIMENS, Assistant Examiner. 

1. A PROCESS FOR INHIBITING IN OIL REFINING APPARATUS DURING PETROLEUM REFINING OPERATIONS THE FORMATION OF ADHERENT SLUDGES ON, AND THE ADHESION OF SAID DEPOSITS AND STICKY SLUGDES ON, AND THE ADHESION OF SAID DEPOSITS AND SAID SLUDGES TO, THE HOT METAL HEAT TRANSFER SURFACES OF A HEAT EXCHANGER IN SAID OIL REFINING APPARATUS BY A HYDROCARBON LIQUID PASSING THROUGH SAID HEAT EXCHANGER AT A TEMPERATURE IN EXCESS OF ABOUT 225*F. AND HAVING THE TENDENCY TO UNDERGO A CHEMICAL REACTION AT A TEMPERATURE IN THE RANGE OF ABOUT 225*F. TO ABOUT 800*F., SAID CHEMICAL REACTION MANIFESTING ITSELF IN THE FORM OF ADHERENT COKE-LIKE DEPOSITS AND ADHERENT SOFT, STICKY SLUDGES, SUCH AS ARE USUALLY FORMED DURING PASSAGE OF SAID HYDROCARBON LIQUID THROUGH SAID HEAT EXCHANGER AND IN CONTACT WITH THE HOT METAL SURFACES OF SAID HEAT EXCHANGER IN SAID OIL REFINING AT A TEMPERATURE IN THE RANGE OF ABOUT 225*F. TO ABOUT 800*F. CHARACTERIZED BY (1) INCORPORATING IN SAID HYDROCARBON LIQUID PRIOR TO CONTACT WITH SAID HOT METAL SURFACES OF SAID HEAT EXCHANGER IN SAID OIL REFINING APPARATUS AN ANTIFOULING AMOUNT OF A COMPOSITION COMPRISING (A) A PARTIAL ESTER SELECTED FROM THE GROUP CONSISTING OF 